Toilet bars based on soap (alkali metal salts of fatty acids) are commonly used for cleansing the human body. A wide variety of additives have been suggested for inclusion in toilet bars to enhance the physical properties of the bar (hardness, wear rate, resistance to water), the use properties of the toilet bar (lather characteristics such as volume and texture), and the impression the bar has on the skin both during washing and afterwards.
For example, lather enhancement has been achieved in several ways. First, soaps derived from shorter chain length fatty acids such as coconut fatty acids are known to produce a much richer lather than soaps produced from longer chain length fatty acids such as tallow fatty acids. It has been common practice in toilet bar manufacture to add up to about 50% coconut fatty acid to the tallow fatty acid feed stock used to make the soap. Second, super fatting agents such as free coconut fatty acid are also known to improve the volume and richness of the lather produced by a toilet bar when it is added to the bars at levels of up to about 10%. At higher levels of addition, however, coconut fatty acid soaps have a detrimental effect on bar mildness while free coconut fatty acids can produce undesirable softening of the bar. Further, coconut soaps and fatty acids are both expensive commodities; it would be desirable to achieve improvements in lathering without recourse to higher levels of such ingredients.
It has also been discovered that the addition of polymeric materials to toilet bars can have a beneficial effect on bar lathering characteristics without deleteriously affecting other bar properties. These polymers should be soluble or dispersible in water to a level of at least 1% by weight, preferably at least 5% by weight at 25.degree. C. Suitable polymers are high molecular weight materials (mass-average molecular weight determined, for instance, by light scattering, being generally from about 20,000 to about 5,000,000, preferably from about 50,000 to about 4,000,000, and more preferably from about 500,000 to about 3,000,000) and preferably have a thickening ability such that a 1% dispersion of the polymer in water at 20.degree. C. exceeds about 1 PaS(10 poise) at a shear rate of 10.sup.-2 sec.sup.-1. Useful polymers are the cationic, nonionic, amphoteric, and anionic polymers useful in the cosmetic field. Preferred are cationic and nonionic resins and mixtures thereof. Highly preferred are the cationic resins. The level of polymer is from about 0.01% to about 5%, preferably from about 0.1% to about 2%. (Unless otherwise specified, all percentages in this specification are percentages by weight.) Suitable cationic polymers include cationic guar gums such as hydroxyproxyltrimethylanmonium guar gum such as that available commercially under the trademarks Jaguar C-17 and Jaguar C-15 as marketed by Hi-Tek Polymers of Louisville, Kentucky. Nonionic polymers include guar gum and hydroxypropyl guar gum.